sheear wall design presentation

8/11/2019 Sheear Wall Design Presentation

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Shear Wall Design process -SCPL design office.

- Parag Kulkarni


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Shear Wall Design Parameters we will be discussing

Applicable codes. Stepwise design process/flow.

Comparison of ETABS and RCDC values. Comparison of RCDC and Spreadsheet values. Comparison of design as a Shear wall and as a

a Column

quantity takeoff. Discussion/Conclusion.


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Sr. Design Criteria Clause / Code1 Max Area of reinforcement 26.5.3.1 a/b

2 Min Area of reinforcement 26.5.3.1 a/b

3 Min Number of bars 26.5.3.1 c

4 Min. eccentricity Calculations 25.4 & 39.2

5 Effective Length 25.2

6 Slenderness Moments 25.3 & 39.7

7 Design for axial loads 39.3

8 Design for axial loads and uni-axial bending 39.5

9 Design for axial loads and biaxial bending 39.6

10 Design of horizontal links 26.5.3.2

11 Design of shear strength 40.2

Design crit

eria and applicable codesIS 456-200


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Sr. Design Criteria Clause / Code1 Spacing of Special confining reinforcement 9.4.5 and 7.4

2 C/s Area of Special confining reinforcement 7.4.7

3 Applicability of boundary element 9.4.1

4 Muv Moment capacity of web Annex A and 9.3

5 Additional comp force in BE 9.4.2

6 Check for BE in tension and compression 9.4.3 and 9.4.4

7 SW general requirement 9.1.1 to 9.1.7

8 SW Shear Strength 9.2.1 to 9.2.6

9 Construction Joints 9.8

10 Development, Splice and Anchorage 9.9

Design criteria and applicable codesIS 13920-1993 Ed 1.2 (02-03)


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Elements of Shear wall

Web

non confining/ non ductile Boundary Elements Confining/ductile Vertical reinforcement and stirrups

For Non confining zone (BE) For Confining zone (Web)

BE Web BE


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Shear Wall in RCDC

1

Acquiring of General Data from ETABS : size of SW, Level, Grade ofSteel/ Concrete, dimensions of wall

Acquiring of Load data; Pu, Mux, Muy, Vux, Vuy

2

Check for requirement of boundary element IS 13920 cl .9.4.1 Minimum eccentricity check IS 456 cl. 25.4 & 39.2 Slenderness check Is 456 cl. 25.3 & 39.7

3

Calculation of DESIGN moment (IS 456 25.4 / 39.2) Picking the max value from M-analysis and M-minecc [Comparing this with ETABS design values].


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Shear Wall in RCDC

4 Biaxial bending check Mux1, Muy1, Pu/Puz and alpha. Interaction ratio < 1 (IS 456 39.5 and 39.6)

5

BE element length as a proportion wrt SW length Calculation of Muv IS 13920- Annex A (Moment by web)

Calculation of Moment by Boundary Element

6

Lever arm and additional force in BE (Lw Length of BE/2) ( but as per IS 13920 this is center to center of BE while RCDC

calculates lever arm i.e. from face of one BE to center of other BE) RCDC gives conservative force in BE


8/11

Shear Wall in RCDC

7

Check for compression capacity of BE Check for tensile capacity of BE Wall configuration table

8

Design for shear along Length of SW (9.2.1 and 9.2.6) Design of shear along breadth of SW

9

Design of links ( Web area i.e. non confining area) IS 13920 7.4 Design of Special Confining reinforcement Links configuration table


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Observations on RCDC and shear walldesign

RCDC designs conservative boundaryelements as the lever arm considered by RCDCis more w.r.t. code specification, This results in

greater moment which is in turn greater axialforce (force couple analogy). RCDC is silent on Cl. 9.8 construction joints

i.e. vert. reinf. ratio = 0.92/fy(Tv-Pu/Ag) it isvery likely that walls are casted in two lifts. All in all RCDC designs are satisfactory.


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Observations on RCDC and shear walldesign

RCDC or ETABS does not correctly design L,T,Cor E shaped shear wall configuration.

Also if shearwall reduce in length in a tallbuilding what is to be done is to be discussed.

A standard drawings for SW elevations isadded to the standard drawings library.


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THANK YOU!

sheear wall design presentation

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